1. Field of the Invention
The present invention relates to a polarizing plate. More specifically, the present invention relates to a polarizing plate having UV-shielding ability.
2. Description of the Related Art
In a liquid crystal display apparatus that is a typical image display apparatus, it is known that polarizing plates are placed on both sides of a liquid crystal cell due to its image forming system. The polarizing plate is generally formed by attaching protective films to both surfaces of a polarizer with an adhesive. As the protective film, typically, a cellulose-based resin film is used.
The polarizer and liquid crystal molecules of the liquid crystal cell are degraded due to UV-light from sunlight or a backlight. In order to prevent the degradation, a cellulose-based resin film containing an organic UV-absorbing agent has been proposed (for example, Japanese Patent Application Laid-open No. 2007-3788). However, such a film has a problem that a UV-absorbing agent bleeds out due to heating at high temperature or variation with time, and the adhesiveness between layers decreases, which makes it impossible to maintain display quality. Further, the organic UV-absorbing agent has a problem that sufficient UV-shielding ability is unlikely to be obtained, and the transparency decreases if the content of the organic UV-absorbing agent is increased.